It's an interesting premise, and one I think that may have changed a bit over recent years. Old school thought was you were either born with the ability to throw 90, or you weren't. However I think some of the more modern training regimens have called that belief into question. I don't think they would claim that anyone can throw 90 - but perhaps through the proper training far more can than was previously believed.
With that said, proper training requires a lot of time and dedication. That is always going to be part of the equation. Also it has to be considered that most of the participants in modern throwing programs aren't just some guy plucked off the streets. These are guys who were already very athletic, which eliminates a huge section of the general population. In other words, a player who would even embark on the training required to get to 90 is probably genetically special from the outset.
It will be interesting to see if Kyle makes an appearance in this thread. I would think he probably has some data that would give some insight one way or another.
Love the idea of Kyle weighing in. Would love to know if they have ever had some kid - hard worker, dedicated - throwing mid 70's as a freshman or sophomore who did everything they asked religiously and just couldn't ever get much past 80. I just think 90 is not god given to most people no matter how hard they work at it.
We have a kid who is probably incapable of throwing any harder than 85 MPH. He is short, left-handed, has chronic back issues, but it doesn't deter him from trying. He sits 75 MPH as a high school senior and collects outs. He'll pitch at a JC for sure, but there's basically no way he'll throw 90 MPH ever.
Anatomy and anthropometry play a huge role. When I saw Tyler Glasnow throw in our facility and break every single velocity record in drills, it didn't shock me. The kid looks like a decathlete, and it turns out it runs in his family. Olympic-caliber genetics go a long long way.
I think 90% of the high school baseball playing population can THROW 85 MPH (not pitch). I do not think 90 MPH is attainable by everyone.
Wish I had a really good, concrete answer for this. The answer unfortunately is that "it depends," but I can narrow it down to body size/type and general athleticism for the most part. Then again, I had a 6'1" fat kid who THREW (pulled down) a maximum of 71 MPH at 15 years old and does not have tall or athletic parents. That same kid sits 95+ MPH now and is every bit of 6'8". Everyone gave up on him at 15. Today he's still not a good athlete, but he throws very hard (up to 98 MPH off the bump) and can hit light tower homers (his college wants him to be a pitcher only, which I understand).
Puberty - and testosterone, specifically - play such a gigantic, unknowable role. And in some respects, that's the fun part of training the underdogs. You really can never tell if they have it or not until they're quite a bit older.
